1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This is the pathetic reminder of old fame of the jump-optimization pass
23 of the compiler. Now it contains basically a set of utility functions to
26 Each CODE_LABEL has a count of the times it is used
27 stored in the LABEL_NUSES internal field, and each JUMP_INSN
28 has one label that it refers to stored in the
29 JUMP_LABEL internal field. With this we can detect labels that
30 become unused because of the deletion of all the jumps that
31 formerly used them. The JUMP_LABEL info is sometimes looked
34 The subroutines redirect_jump and invert_jump are used
35 from other passes as well. */
39 #include "coretypes.h"
44 #include "hard-reg-set.h"
46 #include "insn-config.h"
47 #include "insn-attr.h"
50 #include "basic-block.h"
53 #include "diagnostic-core.h"
57 #include "tree-pass.h"
60 /* Optimize jump y; x: ... y: jumpif... x?
61 Don't know if it is worth bothering with. */
62 /* Optimize two cases of conditional jump to conditional jump?
63 This can never delete any instruction or make anything dead,
64 or even change what is live at any point.
65 So perhaps let combiner do it. */
67 static void init_label_info (rtx
);
68 static void mark_all_labels (rtx
);
69 static void mark_jump_label_1 (rtx
, rtx
, bool, bool);
70 static void mark_jump_label_asm (rtx
, rtx
);
71 static void redirect_exp_1 (rtx
*, rtx
, rtx
, rtx
);
72 static int invert_exp_1 (rtx
, rtx
);
73 static int returnjump_p_1 (rtx
*, void *);
75 /* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET
76 notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping
77 instructions and jumping insns that have labels as operands
80 rebuild_jump_labels (rtx f
)
84 timevar_push (TV_REBUILD_JUMP
);
88 /* Keep track of labels used from static data; we don't track them
89 closely enough to delete them here, so make sure their reference
90 count doesn't drop to zero. */
92 for (insn
= forced_labels
; insn
; insn
= XEXP (insn
, 1))
93 if (LABEL_P (XEXP (insn
, 0)))
94 LABEL_NUSES (XEXP (insn
, 0))++;
95 timevar_pop (TV_REBUILD_JUMP
);
98 /* Some old code expects exactly one BARRIER as the NEXT_INSN of a
99 non-fallthru insn. This is not generally true, as multiple barriers
100 may have crept in, or the BARRIER may be separated from the last
101 real insn by one or more NOTEs.
103 This simple pass moves barriers and removes duplicates so that the
107 cleanup_barriers (void)
109 rtx insn
, next
, prev
;
110 for (insn
= get_insns (); insn
; insn
= next
)
112 next
= NEXT_INSN (insn
);
113 if (BARRIER_P (insn
))
115 prev
= prev_nonnote_insn (insn
);
118 if (BARRIER_P (prev
))
120 else if (prev
!= PREV_INSN (insn
))
121 reorder_insns (insn
, insn
, prev
);
127 struct rtl_opt_pass pass_cleanup_barriers
=
131 "barriers", /* name */
133 cleanup_barriers
, /* execute */
136 0, /* static_pass_number */
138 0, /* properties_required */
139 0, /* properties_provided */
140 0, /* properties_destroyed */
141 0, /* todo_flags_start */
142 TODO_dump_func
/* todo_flags_finish */
147 /* Initialize LABEL_NUSES and JUMP_LABEL fields, add REG_LABEL_TARGET
148 for remaining targets for JUMP_P. Delete any REG_LABEL_OPERAND
149 notes whose labels don't occur in the insn any more. */
152 init_label_info (rtx f
)
156 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
159 LABEL_NUSES (insn
) = (LABEL_PRESERVE_P (insn
) != 0);
161 /* REG_LABEL_TARGET notes (including the JUMP_LABEL field) are
162 sticky and not reset here; that way we won't lose association
163 with a label when e.g. the source for a target register
164 disappears out of reach for targets that may use jump-target
165 registers. Jump transformations are supposed to transform
166 any REG_LABEL_TARGET notes. The target label reference in a
167 branch may disappear from the branch (and from the
168 instruction before it) for other reasons, like register
175 for (note
= REG_NOTES (insn
); note
; note
= next
)
177 next
= XEXP (note
, 1);
178 if (REG_NOTE_KIND (note
) == REG_LABEL_OPERAND
179 && ! reg_mentioned_p (XEXP (note
, 0), PATTERN (insn
)))
180 remove_note (insn
, note
);
186 /* Mark the label each jump jumps to.
187 Combine consecutive labels, and count uses of labels. */
190 mark_all_labels (rtx f
)
193 rtx prev_nonjump_insn
= NULL
;
195 for (insn
= f
; insn
; insn
= NEXT_INSN (insn
))
196 if (NONDEBUG_INSN_P (insn
))
198 mark_jump_label (PATTERN (insn
), insn
, 0);
200 /* If the previous non-jump insn sets something to a label,
201 something that this jump insn uses, make that label the primary
202 target of this insn if we don't yet have any. That previous
203 insn must be a single_set and not refer to more than one label.
204 The jump insn must not refer to other labels as jump targets
205 and must be a plain (set (pc) ...), maybe in a parallel, and
206 may refer to the item being set only directly or as one of the
207 arms in an IF_THEN_ELSE. */
208 if (! INSN_DELETED_P (insn
)
210 && JUMP_LABEL (insn
) == NULL
)
212 rtx label_note
= NULL
;
213 rtx pc
= pc_set (insn
);
214 rtx pc_src
= pc
!= NULL
? SET_SRC (pc
) : NULL
;
216 if (prev_nonjump_insn
!= NULL
)
218 = find_reg_note (prev_nonjump_insn
, REG_LABEL_OPERAND
, NULL
);
220 if (label_note
!= NULL
&& pc_src
!= NULL
)
222 rtx label_set
= single_set (prev_nonjump_insn
);
224 = label_set
!= NULL
? SET_DEST (label_set
) : NULL
;
226 if (label_set
!= NULL
227 /* The source must be the direct LABEL_REF, not a
228 PLUS, UNSPEC, IF_THEN_ELSE etc. */
229 && GET_CODE (SET_SRC (label_set
)) == LABEL_REF
230 && (rtx_equal_p (label_dest
, pc_src
)
231 || (GET_CODE (pc_src
) == IF_THEN_ELSE
232 && (rtx_equal_p (label_dest
, XEXP (pc_src
, 1))
233 || rtx_equal_p (label_dest
,
234 XEXP (pc_src
, 2))))))
237 /* The CODE_LABEL referred to in the note must be the
238 CODE_LABEL in the LABEL_REF of the "set". We can
239 conveniently use it for the marker function, which
240 requires a LABEL_REF wrapping. */
241 gcc_assert (XEXP (label_note
, 0)
242 == XEXP (SET_SRC (label_set
), 0));
244 mark_jump_label_1 (label_set
, insn
, false, true);
245 gcc_assert (JUMP_LABEL (insn
)
246 == XEXP (SET_SRC (label_set
), 0));
250 else if (! INSN_DELETED_P (insn
))
251 prev_nonjump_insn
= insn
;
253 else if (LABEL_P (insn
))
254 prev_nonjump_insn
= NULL
;
256 /* If we are in cfglayout mode, there may be non-insns between the
257 basic blocks. If those non-insns represent tablejump data, they
258 contain label references that we must record. */
259 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
265 for (insn
= bb
->il
.rtl
->header
; insn
; insn
= NEXT_INSN (insn
))
268 gcc_assert (JUMP_TABLE_DATA_P (insn
));
269 mark_jump_label (PATTERN (insn
), insn
, 0);
272 for (insn
= bb
->il
.rtl
->footer
; insn
; insn
= NEXT_INSN (insn
))
275 gcc_assert (JUMP_TABLE_DATA_P (insn
));
276 mark_jump_label (PATTERN (insn
), insn
, 0);
282 /* Given a comparison (CODE ARG0 ARG1), inside an insn, INSN, return a code
283 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
284 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
285 know whether it's source is floating point or integer comparison. Machine
286 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
287 to help this function avoid overhead in these cases. */
289 reversed_comparison_code_parts (enum rtx_code code
, const_rtx arg0
,
290 const_rtx arg1
, const_rtx insn
)
292 enum machine_mode mode
;
294 /* If this is not actually a comparison, we can't reverse it. */
295 if (GET_RTX_CLASS (code
) != RTX_COMPARE
296 && GET_RTX_CLASS (code
) != RTX_COMM_COMPARE
)
299 mode
= GET_MODE (arg0
);
300 if (mode
== VOIDmode
)
301 mode
= GET_MODE (arg1
);
303 /* First see if machine description supplies us way to reverse the
304 comparison. Give it priority over everything else to allow
305 machine description to do tricks. */
306 if (GET_MODE_CLASS (mode
) == MODE_CC
307 && REVERSIBLE_CC_MODE (mode
))
309 #ifdef REVERSE_CONDITION
310 return REVERSE_CONDITION (code
, mode
);
312 return reverse_condition (code
);
316 /* Try a few special cases based on the comparison code. */
325 /* It is always safe to reverse EQ and NE, even for the floating
326 point. Similarly the unsigned comparisons are never used for
327 floating point so we can reverse them in the default way. */
328 return reverse_condition (code
);
333 /* In case we already see unordered comparison, we can be sure to
334 be dealing with floating point so we don't need any more tests. */
335 return reverse_condition_maybe_unordered (code
);
340 /* We don't have safe way to reverse these yet. */
346 if (GET_MODE_CLASS (mode
) == MODE_CC
|| CC0_P (arg0
))
349 /* Try to search for the comparison to determine the real mode.
350 This code is expensive, but with sane machine description it
351 will be never used, since REVERSIBLE_CC_MODE will return true
356 /* These CONST_CAST's are okay because prev_nonnote_insn just
357 returns its argument and we assign it to a const_rtx
359 for (prev
= prev_nonnote_insn (CONST_CAST_RTX(insn
));
360 prev
!= 0 && !LABEL_P (prev
);
361 prev
= prev_nonnote_insn (CONST_CAST_RTX(prev
)))
363 const_rtx set
= set_of (arg0
, prev
);
364 if (set
&& GET_CODE (set
) == SET
365 && rtx_equal_p (SET_DEST (set
), arg0
))
367 rtx src
= SET_SRC (set
);
369 if (GET_CODE (src
) == COMPARE
)
371 rtx comparison
= src
;
372 arg0
= XEXP (src
, 0);
373 mode
= GET_MODE (arg0
);
374 if (mode
== VOIDmode
)
375 mode
= GET_MODE (XEXP (comparison
, 1));
378 /* We can get past reg-reg moves. This may be useful for model
379 of i387 comparisons that first move flag registers around. */
386 /* If register is clobbered in some ununderstandable way,
393 /* Test for an integer condition, or a floating-point comparison
394 in which NaNs can be ignored. */
395 if (CONST_INT_P (arg0
)
396 || (GET_MODE (arg0
) != VOIDmode
397 && GET_MODE_CLASS (mode
) != MODE_CC
398 && !HONOR_NANS (mode
)))
399 return reverse_condition (code
);
404 /* A wrapper around the previous function to take COMPARISON as rtx
405 expression. This simplifies many callers. */
407 reversed_comparison_code (const_rtx comparison
, const_rtx insn
)
409 if (!COMPARISON_P (comparison
))
411 return reversed_comparison_code_parts (GET_CODE (comparison
),
412 XEXP (comparison
, 0),
413 XEXP (comparison
, 1), insn
);
416 /* Return comparison with reversed code of EXP.
417 Return NULL_RTX in case we fail to do the reversal. */
419 reversed_comparison (const_rtx exp
, enum machine_mode mode
)
421 enum rtx_code reversed_code
= reversed_comparison_code (exp
, NULL_RTX
);
422 if (reversed_code
== UNKNOWN
)
425 return simplify_gen_relational (reversed_code
, mode
, VOIDmode
,
426 XEXP (exp
, 0), XEXP (exp
, 1));
430 /* Given an rtx-code for a comparison, return the code for the negated
431 comparison. If no such code exists, return UNKNOWN.
433 WATCH OUT! reverse_condition is not safe to use on a jump that might
434 be acting on the results of an IEEE floating point comparison, because
435 of the special treatment of non-signaling nans in comparisons.
436 Use reversed_comparison_code instead. */
439 reverse_condition (enum rtx_code code
)
481 /* Similar, but we're allowed to generate unordered comparisons, which
482 makes it safe for IEEE floating-point. Of course, we have to recognize
483 that the target will support them too... */
486 reverse_condition_maybe_unordered (enum rtx_code code
)
524 /* Similar, but return the code when two operands of a comparison are swapped.
525 This IS safe for IEEE floating-point. */
528 swap_condition (enum rtx_code code
)
570 /* Given a comparison CODE, return the corresponding unsigned comparison.
571 If CODE is an equality comparison or already an unsigned comparison,
575 unsigned_condition (enum rtx_code code
)
601 /* Similarly, return the signed version of a comparison. */
604 signed_condition (enum rtx_code code
)
630 /* Return nonzero if CODE1 is more strict than CODE2, i.e., if the
631 truth of CODE1 implies the truth of CODE2. */
634 comparison_dominates_p (enum rtx_code code1
, enum rtx_code code2
)
636 /* UNKNOWN comparison codes can happen as a result of trying to revert
638 They can't match anything, so we have to reject them here. */
639 if (code1
== UNKNOWN
|| code2
== UNKNOWN
)
648 if (code2
== UNLE
|| code2
== UNGE
)
653 if (code2
== LE
|| code2
== LEU
|| code2
== GE
|| code2
== GEU
659 if (code2
== UNLE
|| code2
== NE
)
664 if (code2
== LE
|| code2
== NE
|| code2
== ORDERED
|| code2
== LTGT
)
669 if (code2
== UNGE
|| code2
== NE
)
674 if (code2
== GE
|| code2
== NE
|| code2
== ORDERED
|| code2
== LTGT
)
680 if (code2
== ORDERED
)
685 if (code2
== NE
|| code2
== ORDERED
)
690 if (code2
== LEU
|| code2
== NE
)
695 if (code2
== GEU
|| code2
== NE
)
700 if (code2
== NE
|| code2
== UNEQ
|| code2
== UNLE
|| code2
== UNLT
701 || code2
== UNGE
|| code2
== UNGT
)
712 /* Return 1 if INSN is an unconditional jump and nothing else. */
715 simplejump_p (const_rtx insn
)
717 return (JUMP_P (insn
)
718 && GET_CODE (PATTERN (insn
)) == SET
719 && GET_CODE (SET_DEST (PATTERN (insn
))) == PC
720 && GET_CODE (SET_SRC (PATTERN (insn
))) == LABEL_REF
);
723 /* Return nonzero if INSN is a (possibly) conditional jump
726 Use of this function is deprecated, since we need to support combined
727 branch and compare insns. Use any_condjump_p instead whenever possible. */
730 condjump_p (const_rtx insn
)
732 const_rtx x
= PATTERN (insn
);
734 if (GET_CODE (x
) != SET
735 || GET_CODE (SET_DEST (x
)) != PC
)
739 if (GET_CODE (x
) == LABEL_REF
)
742 return (GET_CODE (x
) == IF_THEN_ELSE
743 && ((GET_CODE (XEXP (x
, 2)) == PC
744 && (GET_CODE (XEXP (x
, 1)) == LABEL_REF
745 || GET_CODE (XEXP (x
, 1)) == RETURN
))
746 || (GET_CODE (XEXP (x
, 1)) == PC
747 && (GET_CODE (XEXP (x
, 2)) == LABEL_REF
748 || GET_CODE (XEXP (x
, 2)) == RETURN
))));
751 /* Return nonzero if INSN is a (possibly) conditional jump inside a
754 Use this function is deprecated, since we need to support combined
755 branch and compare insns. Use any_condjump_p instead whenever possible. */
758 condjump_in_parallel_p (const_rtx insn
)
760 const_rtx x
= PATTERN (insn
);
762 if (GET_CODE (x
) != PARALLEL
)
765 x
= XVECEXP (x
, 0, 0);
767 if (GET_CODE (x
) != SET
)
769 if (GET_CODE (SET_DEST (x
)) != PC
)
771 if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
773 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
775 if (XEXP (SET_SRC (x
), 2) == pc_rtx
776 && (GET_CODE (XEXP (SET_SRC (x
), 1)) == LABEL_REF
777 || GET_CODE (XEXP (SET_SRC (x
), 1)) == RETURN
))
779 if (XEXP (SET_SRC (x
), 1) == pc_rtx
780 && (GET_CODE (XEXP (SET_SRC (x
), 2)) == LABEL_REF
781 || GET_CODE (XEXP (SET_SRC (x
), 2)) == RETURN
))
786 /* Return set of PC, otherwise NULL. */
789 pc_set (const_rtx insn
)
794 pat
= PATTERN (insn
);
796 /* The set is allowed to appear either as the insn pattern or
797 the first set in a PARALLEL. */
798 if (GET_CODE (pat
) == PARALLEL
)
799 pat
= XVECEXP (pat
, 0, 0);
800 if (GET_CODE (pat
) == SET
&& GET_CODE (SET_DEST (pat
)) == PC
)
806 /* Return true when insn is an unconditional direct jump,
807 possibly bundled inside a PARALLEL. */
810 any_uncondjump_p (const_rtx insn
)
812 const_rtx x
= pc_set (insn
);
815 if (GET_CODE (SET_SRC (x
)) != LABEL_REF
)
817 if (find_reg_note (insn
, REG_NON_LOCAL_GOTO
, NULL_RTX
))
822 /* Return true when insn is a conditional jump. This function works for
823 instructions containing PC sets in PARALLELs. The instruction may have
824 various other effects so before removing the jump you must verify
827 Note that unlike condjump_p it returns false for unconditional jumps. */
830 any_condjump_p (const_rtx insn
)
832 const_rtx x
= pc_set (insn
);
837 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
840 a
= GET_CODE (XEXP (SET_SRC (x
), 1));
841 b
= GET_CODE (XEXP (SET_SRC (x
), 2));
843 return ((b
== PC
&& (a
== LABEL_REF
|| a
== RETURN
))
844 || (a
== PC
&& (b
== LABEL_REF
|| b
== RETURN
)));
847 /* Return the label of a conditional jump. */
850 condjump_label (const_rtx insn
)
852 rtx x
= pc_set (insn
);
857 if (GET_CODE (x
) == LABEL_REF
)
859 if (GET_CODE (x
) != IF_THEN_ELSE
)
861 if (XEXP (x
, 2) == pc_rtx
&& GET_CODE (XEXP (x
, 1)) == LABEL_REF
)
863 if (XEXP (x
, 1) == pc_rtx
&& GET_CODE (XEXP (x
, 2)) == LABEL_REF
)
868 /* Return true if INSN is a (possibly conditional) return insn. */
871 returnjump_p_1 (rtx
*loc
, void *data ATTRIBUTE_UNUSED
)
878 switch (GET_CODE (x
))
885 return SET_IS_RETURN_P (x
);
892 /* Return TRUE if INSN is a return jump. */
895 returnjump_p (rtx insn
)
899 return for_each_rtx (&PATTERN (insn
), returnjump_p_1
, NULL
);
902 /* Return true if INSN is a (possibly conditional) return insn. */
905 eh_returnjump_p_1 (rtx
*loc
, void *data ATTRIBUTE_UNUSED
)
907 return *loc
&& GET_CODE (*loc
) == EH_RETURN
;
911 eh_returnjump_p (rtx insn
)
915 return for_each_rtx (&PATTERN (insn
), eh_returnjump_p_1
, NULL
);
918 /* Return true if INSN is a jump that only transfers control and
922 onlyjump_p (const_rtx insn
)
929 set
= single_set (insn
);
932 if (GET_CODE (SET_DEST (set
)) != PC
)
934 if (side_effects_p (SET_SRC (set
)))
942 /* Return nonzero if X is an RTX that only sets the condition codes
943 and has no side effects. */
946 only_sets_cc0_p (const_rtx x
)
954 return sets_cc0_p (x
) == 1 && ! side_effects_p (x
);
957 /* Return 1 if X is an RTX that does nothing but set the condition codes
958 and CLOBBER or USE registers.
959 Return -1 if X does explicitly set the condition codes,
960 but also does other things. */
963 sets_cc0_p (const_rtx x
)
971 if (GET_CODE (x
) == SET
&& SET_DEST (x
) == cc0_rtx
)
973 if (GET_CODE (x
) == PARALLEL
)
977 int other_things
= 0;
978 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
980 if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
981 && SET_DEST (XVECEXP (x
, 0, i
)) == cc0_rtx
)
983 else if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
)
986 return ! sets_cc0
? 0 : other_things
? -1 : 1;
992 /* Find all CODE_LABELs referred to in X, and increment their use
993 counts. If INSN is a JUMP_INSN and there is at least one
994 CODE_LABEL referenced in INSN as a jump target, then store the last
995 one in JUMP_LABEL (INSN). For a tablejump, this must be the label
996 for the ADDR_VEC. Store any other jump targets as REG_LABEL_TARGET
997 notes. If INSN is an INSN or a CALL_INSN or non-target operands of
998 a JUMP_INSN, and there is at least one CODE_LABEL referenced in
999 INSN, add a REG_LABEL_OPERAND note containing that label to INSN.
1001 Note that two labels separated by a loop-beginning note
1002 must be kept distinct if we have not yet done loop-optimization,
1003 because the gap between them is where loop-optimize
1004 will want to move invariant code to. CROSS_JUMP tells us
1005 that loop-optimization is done with. */
1008 mark_jump_label (rtx x
, rtx insn
, int in_mem
)
1010 rtx asmop
= extract_asm_operands (x
);
1012 mark_jump_label_asm (asmop
, insn
);
1014 mark_jump_label_1 (x
, insn
, in_mem
!= 0,
1015 (insn
!= NULL
&& x
== PATTERN (insn
) && JUMP_P (insn
)));
1018 /* Worker function for mark_jump_label. IN_MEM is TRUE when X occurs
1019 within a (MEM ...). IS_TARGET is TRUE when X is to be treated as a
1020 jump-target; when the JUMP_LABEL field of INSN should be set or a
1021 REG_LABEL_TARGET note should be added, not a REG_LABEL_OPERAND
1025 mark_jump_label_1 (rtx x
, rtx insn
, bool in_mem
, bool is_target
)
1027 RTX_CODE code
= GET_CODE (x
);
1047 for (i
= 0; i
< XVECLEN (x
, 0); i
++)
1048 mark_jump_label (PATTERN (XVECEXP (x
, 0, i
)),
1049 XVECEXP (x
, 0, i
), 0);
1056 /* If this is a constant-pool reference, see if it is a label. */
1057 if (CONSTANT_POOL_ADDRESS_P (x
))
1058 mark_jump_label_1 (get_pool_constant (x
), insn
, in_mem
, is_target
);
1061 /* Handle operands in the condition of an if-then-else as for a
1066 mark_jump_label_1 (XEXP (x
, 0), insn
, in_mem
, false);
1067 mark_jump_label_1 (XEXP (x
, 1), insn
, in_mem
, true);
1068 mark_jump_label_1 (XEXP (x
, 2), insn
, in_mem
, true);
1073 rtx label
= XEXP (x
, 0);
1075 /* Ignore remaining references to unreachable labels that
1076 have been deleted. */
1078 && NOTE_KIND (label
) == NOTE_INSN_DELETED_LABEL
)
1081 gcc_assert (LABEL_P (label
));
1083 /* Ignore references to labels of containing functions. */
1084 if (LABEL_REF_NONLOCAL_P (x
))
1087 XEXP (x
, 0) = label
;
1088 if (! insn
|| ! INSN_DELETED_P (insn
))
1089 ++LABEL_NUSES (label
);
1094 /* Do not change a previous setting of JUMP_LABEL. If the
1095 JUMP_LABEL slot is occupied by a different label,
1096 create a note for this label. */
1097 && (JUMP_LABEL (insn
) == NULL
|| JUMP_LABEL (insn
) == label
))
1098 JUMP_LABEL (insn
) = label
;
1102 = is_target
? REG_LABEL_TARGET
: REG_LABEL_OPERAND
;
1104 /* Add a REG_LABEL_OPERAND or REG_LABEL_TARGET note
1105 for LABEL unless there already is one. All uses of
1106 a label, except for the primary target of a jump,
1107 must have such a note. */
1108 if (! find_reg_note (insn
, kind
, label
))
1109 add_reg_note (insn
, kind
, label
);
1115 /* Do walk the labels in a vector, but not the first operand of an
1116 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
1119 if (! INSN_DELETED_P (insn
))
1121 int eltnum
= code
== ADDR_DIFF_VEC
? 1 : 0;
1123 for (i
= 0; i
< XVECLEN (x
, eltnum
); i
++)
1124 mark_jump_label_1 (XVECEXP (x
, eltnum
, i
), NULL_RTX
, in_mem
,
1133 fmt
= GET_RTX_FORMAT (code
);
1135 /* The primary target of a tablejump is the label of the ADDR_VEC,
1136 which is canonically mentioned *last* in the insn. To get it
1137 marked as JUMP_LABEL, we iterate over items in reverse order. */
1138 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1141 mark_jump_label_1 (XEXP (x
, i
), insn
, in_mem
, is_target
);
1142 else if (fmt
[i
] == 'E')
1146 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
1147 mark_jump_label_1 (XVECEXP (x
, i
, j
), insn
, in_mem
,
1153 /* Worker function for mark_jump_label. Handle asm insns specially.
1154 In particular, output operands need not be considered so we can
1155 avoid re-scanning the replicated asm_operand. Also, the asm_labels
1156 need to be considered targets. */
1159 mark_jump_label_asm (rtx asmop
, rtx insn
)
1163 for (i
= ASM_OPERANDS_INPUT_LENGTH (asmop
) - 1; i
>= 0; --i
)
1164 mark_jump_label_1 (ASM_OPERANDS_INPUT (asmop
, i
), insn
, false, false);
1166 for (i
= ASM_OPERANDS_LABEL_LENGTH (asmop
) - 1; i
>= 0; --i
)
1167 mark_jump_label_1 (ASM_OPERANDS_LABEL (asmop
, i
), insn
, false, true);
1170 /* Delete insn INSN from the chain of insns and update label ref counts
1171 and delete insns now unreachable.
1173 Returns the first insn after INSN that was not deleted.
1175 Usage of this instruction is deprecated. Use delete_insn instead and
1176 subsequent cfg_cleanup pass to delete unreachable code if needed. */
1179 delete_related_insns (rtx insn
)
1181 int was_code_label
= (LABEL_P (insn
));
1183 rtx next
= NEXT_INSN (insn
), prev
= PREV_INSN (insn
);
1185 while (next
&& INSN_DELETED_P (next
))
1186 next
= NEXT_INSN (next
);
1188 /* This insn is already deleted => return first following nondeleted. */
1189 if (INSN_DELETED_P (insn
))
1194 /* If instruction is followed by a barrier,
1195 delete the barrier too. */
1197 if (next
!= 0 && BARRIER_P (next
))
1200 /* If deleting a jump, decrement the count of the label,
1201 and delete the label if it is now unused. */
1203 if (JUMP_P (insn
) && JUMP_LABEL (insn
))
1205 rtx lab
= JUMP_LABEL (insn
), lab_next
;
1207 if (LABEL_NUSES (lab
) == 0)
1208 /* This can delete NEXT or PREV,
1209 either directly if NEXT is JUMP_LABEL (INSN),
1210 or indirectly through more levels of jumps. */
1211 delete_related_insns (lab
);
1212 else if (tablejump_p (insn
, NULL
, &lab_next
))
1214 /* If we're deleting the tablejump, delete the dispatch table.
1215 We may not be able to kill the label immediately preceding
1216 just yet, as it might be referenced in code leading up to
1218 delete_related_insns (lab_next
);
1222 /* Likewise if we're deleting a dispatch table. */
1224 if (JUMP_TABLE_DATA_P (insn
))
1226 rtx pat
= PATTERN (insn
);
1227 int i
, diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
1228 int len
= XVECLEN (pat
, diff_vec_p
);
1230 for (i
= 0; i
< len
; i
++)
1231 if (LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)) == 0)
1232 delete_related_insns (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0));
1233 while (next
&& INSN_DELETED_P (next
))
1234 next
= NEXT_INSN (next
);
1238 /* Likewise for any JUMP_P / INSN / CALL_INSN with a
1239 REG_LABEL_OPERAND or REG_LABEL_TARGET note. */
1241 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
1242 if ((REG_NOTE_KIND (note
) == REG_LABEL_OPERAND
1243 || REG_NOTE_KIND (note
) == REG_LABEL_TARGET
)
1244 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
1245 && LABEL_P (XEXP (note
, 0)))
1246 if (LABEL_NUSES (XEXP (note
, 0)) == 0)
1247 delete_related_insns (XEXP (note
, 0));
1249 while (prev
&& (INSN_DELETED_P (prev
) || NOTE_P (prev
)))
1250 prev
= PREV_INSN (prev
);
1252 /* If INSN was a label and a dispatch table follows it,
1253 delete the dispatch table. The tablejump must have gone already.
1254 It isn't useful to fall through into a table. */
1257 && NEXT_INSN (insn
) != 0
1258 && JUMP_TABLE_DATA_P (NEXT_INSN (insn
)))
1259 next
= delete_related_insns (NEXT_INSN (insn
));
1261 /* If INSN was a label, delete insns following it if now unreachable. */
1263 if (was_code_label
&& prev
&& BARRIER_P (prev
))
1268 code
= GET_CODE (next
);
1270 next
= NEXT_INSN (next
);
1271 /* Keep going past other deleted labels to delete what follows. */
1272 else if (code
== CODE_LABEL
&& INSN_DELETED_P (next
))
1273 next
= NEXT_INSN (next
);
1274 else if (code
== BARRIER
|| INSN_P (next
))
1275 /* Note: if this deletes a jump, it can cause more
1276 deletion of unreachable code, after a different label.
1277 As long as the value from this recursive call is correct,
1278 this invocation functions correctly. */
1279 next
= delete_related_insns (next
);
1285 /* I feel a little doubtful about this loop,
1286 but I see no clean and sure alternative way
1287 to find the first insn after INSN that is not now deleted.
1288 I hope this works. */
1289 while (next
&& INSN_DELETED_P (next
))
1290 next
= NEXT_INSN (next
);
1294 /* Delete a range of insns from FROM to TO, inclusive.
1295 This is for the sake of peephole optimization, so assume
1296 that whatever these insns do will still be done by a new
1297 peephole insn that will replace them. */
1300 delete_for_peephole (rtx from
, rtx to
)
1306 rtx next
= NEXT_INSN (insn
);
1307 rtx prev
= PREV_INSN (insn
);
1311 INSN_DELETED_P (insn
) = 1;
1313 /* Patch this insn out of the chain. */
1314 /* We don't do this all at once, because we
1315 must preserve all NOTEs. */
1317 NEXT_INSN (prev
) = next
;
1320 PREV_INSN (next
) = prev
;
1328 /* Note that if TO is an unconditional jump
1329 we *do not* delete the BARRIER that follows,
1330 since the peephole that replaces this sequence
1331 is also an unconditional jump in that case. */
1334 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
1335 NLABEL as a return. Accrue modifications into the change group. */
1338 redirect_exp_1 (rtx
*loc
, rtx olabel
, rtx nlabel
, rtx insn
)
1341 RTX_CODE code
= GET_CODE (x
);
1345 if (code
== LABEL_REF
)
1347 if (XEXP (x
, 0) == olabel
)
1351 n
= gen_rtx_LABEL_REF (Pmode
, nlabel
);
1353 n
= gen_rtx_RETURN (VOIDmode
);
1355 validate_change (insn
, loc
, n
, 1);
1359 else if (code
== RETURN
&& olabel
== 0)
1362 x
= gen_rtx_LABEL_REF (Pmode
, nlabel
);
1364 x
= gen_rtx_RETURN (VOIDmode
);
1365 if (loc
== &PATTERN (insn
))
1366 x
= gen_rtx_SET (VOIDmode
, pc_rtx
, x
);
1367 validate_change (insn
, loc
, x
, 1);
1371 if (code
== SET
&& nlabel
== 0 && SET_DEST (x
) == pc_rtx
1372 && GET_CODE (SET_SRC (x
)) == LABEL_REF
1373 && XEXP (SET_SRC (x
), 0) == olabel
)
1375 validate_change (insn
, loc
, gen_rtx_RETURN (VOIDmode
), 1);
1379 if (code
== IF_THEN_ELSE
)
1381 /* Skip the condition of an IF_THEN_ELSE. We only want to
1382 change jump destinations, not eventual label comparisons. */
1383 redirect_exp_1 (&XEXP (x
, 1), olabel
, nlabel
, insn
);
1384 redirect_exp_1 (&XEXP (x
, 2), olabel
, nlabel
, insn
);
1388 fmt
= GET_RTX_FORMAT (code
);
1389 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1392 redirect_exp_1 (&XEXP (x
, i
), olabel
, nlabel
, insn
);
1393 else if (fmt
[i
] == 'E')
1396 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1397 redirect_exp_1 (&XVECEXP (x
, i
, j
), olabel
, nlabel
, insn
);
1402 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
1403 the modifications into the change group. Return false if we did
1404 not see how to do that. */
1407 redirect_jump_1 (rtx jump
, rtx nlabel
)
1409 int ochanges
= num_validated_changes ();
1412 asmop
= extract_asm_operands (PATTERN (jump
));
1417 gcc_assert (ASM_OPERANDS_LABEL_LENGTH (asmop
) == 1);
1418 loc
= &ASM_OPERANDS_LABEL (asmop
, 0);
1420 else if (GET_CODE (PATTERN (jump
)) == PARALLEL
)
1421 loc
= &XVECEXP (PATTERN (jump
), 0, 0);
1423 loc
= &PATTERN (jump
);
1425 redirect_exp_1 (loc
, JUMP_LABEL (jump
), nlabel
, jump
);
1426 return num_validated_changes () > ochanges
;
1429 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
1430 jump target label is unused as a result, it and the code following
1433 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
1436 The return value will be 1 if the change was made, 0 if it wasn't
1437 (this can only occur for NLABEL == 0). */
1440 redirect_jump (rtx jump
, rtx nlabel
, int delete_unused
)
1442 rtx olabel
= JUMP_LABEL (jump
);
1444 if (nlabel
== olabel
)
1447 if (! redirect_jump_1 (jump
, nlabel
) || ! apply_change_group ())
1450 redirect_jump_2 (jump
, olabel
, nlabel
, delete_unused
, 0);
1454 /* Fix up JUMP_LABEL and label ref counts after OLABEL has been replaced with
1456 If DELETE_UNUSED is positive, delete related insn to OLABEL if its ref
1457 count has dropped to zero. */
1459 redirect_jump_2 (rtx jump
, rtx olabel
, rtx nlabel
, int delete_unused
,
1464 gcc_assert (JUMP_LABEL (jump
) == olabel
);
1466 /* Negative DELETE_UNUSED used to be used to signalize behavior on
1467 moving FUNCTION_END note. Just sanity check that no user still worry
1469 gcc_assert (delete_unused
>= 0);
1470 JUMP_LABEL (jump
) = nlabel
;
1472 ++LABEL_NUSES (nlabel
);
1474 /* Update labels in any REG_EQUAL note. */
1475 if ((note
= find_reg_note (jump
, REG_EQUAL
, NULL_RTX
)) != NULL_RTX
)
1477 if (!nlabel
|| (invert
&& !invert_exp_1 (XEXP (note
, 0), jump
)))
1478 remove_note (jump
, note
);
1481 redirect_exp_1 (&XEXP (note
, 0), olabel
, nlabel
, jump
);
1482 confirm_change_group ();
1486 if (olabel
&& --LABEL_NUSES (olabel
) == 0 && delete_unused
> 0
1487 /* Undefined labels will remain outside the insn stream. */
1488 && INSN_UID (olabel
))
1489 delete_related_insns (olabel
);
1491 invert_br_probabilities (jump
);
1494 /* Invert the jump condition X contained in jump insn INSN. Accrue the
1495 modifications into the change group. Return nonzero for success. */
1497 invert_exp_1 (rtx x
, rtx insn
)
1499 RTX_CODE code
= GET_CODE (x
);
1501 if (code
== IF_THEN_ELSE
)
1503 rtx comp
= XEXP (x
, 0);
1505 enum rtx_code reversed_code
;
1507 /* We can do this in two ways: The preferable way, which can only
1508 be done if this is not an integer comparison, is to reverse
1509 the comparison code. Otherwise, swap the THEN-part and ELSE-part
1510 of the IF_THEN_ELSE. If we can't do either, fail. */
1512 reversed_code
= reversed_comparison_code (comp
, insn
);
1514 if (reversed_code
!= UNKNOWN
)
1516 validate_change (insn
, &XEXP (x
, 0),
1517 gen_rtx_fmt_ee (reversed_code
,
1518 GET_MODE (comp
), XEXP (comp
, 0),
1525 validate_change (insn
, &XEXP (x
, 1), XEXP (x
, 2), 1);
1526 validate_change (insn
, &XEXP (x
, 2), tem
, 1);
1533 /* Invert the condition of the jump JUMP, and make it jump to label
1534 NLABEL instead of where it jumps now. Accrue changes into the
1535 change group. Return false if we didn't see how to perform the
1536 inversion and redirection. */
1539 invert_jump_1 (rtx jump
, rtx nlabel
)
1541 rtx x
= pc_set (jump
);
1545 ochanges
= num_validated_changes ();
1548 ok
= invert_exp_1 (SET_SRC (x
), jump
);
1551 if (num_validated_changes () == ochanges
)
1554 /* redirect_jump_1 will fail of nlabel == olabel, and the current use is
1555 in Pmode, so checking this is not merely an optimization. */
1556 return nlabel
== JUMP_LABEL (jump
) || redirect_jump_1 (jump
, nlabel
);
1559 /* Invert the condition of the jump JUMP, and make it jump to label
1560 NLABEL instead of where it jumps now. Return true if successful. */
1563 invert_jump (rtx jump
, rtx nlabel
, int delete_unused
)
1565 rtx olabel
= JUMP_LABEL (jump
);
1567 if (invert_jump_1 (jump
, nlabel
) && apply_change_group ())
1569 redirect_jump_2 (jump
, olabel
, nlabel
, delete_unused
, 1);
1577 /* Like rtx_equal_p except that it considers two REGs as equal
1578 if they renumber to the same value and considers two commutative
1579 operations to be the same if the order of the operands has been
1583 rtx_renumbered_equal_p (const_rtx x
, const_rtx y
)
1586 const enum rtx_code code
= GET_CODE (x
);
1592 if ((code
== REG
|| (code
== SUBREG
&& REG_P (SUBREG_REG (x
))))
1593 && (REG_P (y
) || (GET_CODE (y
) == SUBREG
1594 && REG_P (SUBREG_REG (y
)))))
1596 int reg_x
= -1, reg_y
= -1;
1597 int byte_x
= 0, byte_y
= 0;
1598 struct subreg_info info
;
1600 if (GET_MODE (x
) != GET_MODE (y
))
1603 /* If we haven't done any renumbering, don't
1604 make any assumptions. */
1605 if (reg_renumber
== 0)
1606 return rtx_equal_p (x
, y
);
1610 reg_x
= REGNO (SUBREG_REG (x
));
1611 byte_x
= SUBREG_BYTE (x
);
1613 if (reg_renumber
[reg_x
] >= 0)
1615 subreg_get_info (reg_renumber
[reg_x
],
1616 GET_MODE (SUBREG_REG (x
)), byte_x
,
1617 GET_MODE (x
), &info
);
1618 if (!info
.representable_p
)
1620 reg_x
= info
.offset
;
1627 if (reg_renumber
[reg_x
] >= 0)
1628 reg_x
= reg_renumber
[reg_x
];
1631 if (GET_CODE (y
) == SUBREG
)
1633 reg_y
= REGNO (SUBREG_REG (y
));
1634 byte_y
= SUBREG_BYTE (y
);
1636 if (reg_renumber
[reg_y
] >= 0)
1638 subreg_get_info (reg_renumber
[reg_y
],
1639 GET_MODE (SUBREG_REG (y
)), byte_y
,
1640 GET_MODE (y
), &info
);
1641 if (!info
.representable_p
)
1643 reg_y
= info
.offset
;
1650 if (reg_renumber
[reg_y
] >= 0)
1651 reg_y
= reg_renumber
[reg_y
];
1654 return reg_x
>= 0 && reg_x
== reg_y
&& byte_x
== byte_y
;
1657 /* Now we have disposed of all the cases
1658 in which different rtx codes can match. */
1659 if (code
!= GET_CODE (y
))
1673 /* We can't assume nonlocal labels have their following insns yet. */
1674 if (LABEL_REF_NONLOCAL_P (x
) || LABEL_REF_NONLOCAL_P (y
))
1675 return XEXP (x
, 0) == XEXP (y
, 0);
1677 /* Two label-refs are equivalent if they point at labels
1678 in the same position in the instruction stream. */
1679 return (next_real_insn (XEXP (x
, 0))
1680 == next_real_insn (XEXP (y
, 0)));
1683 return XSTR (x
, 0) == XSTR (y
, 0);
1686 /* If we didn't match EQ equality above, they aren't the same. */
1693 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
1695 if (GET_MODE (x
) != GET_MODE (y
))
1698 /* MEMs refering to different address space are not equivalent. */
1699 if (code
== MEM
&& MEM_ADDR_SPACE (x
) != MEM_ADDR_SPACE (y
))
1702 /* For commutative operations, the RTX match if the operand match in any
1703 order. Also handle the simple binary and unary cases without a loop. */
1704 if (targetm
.commutative_p (x
, UNKNOWN
))
1705 return ((rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
1706 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)))
1707 || (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 1))
1708 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 0))));
1709 else if (NON_COMMUTATIVE_P (x
))
1710 return (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
1711 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)));
1712 else if (UNARY_P (x
))
1713 return rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0));
1715 /* Compare the elements. If any pair of corresponding elements
1716 fail to match, return 0 for the whole things. */
1718 fmt
= GET_RTX_FORMAT (code
);
1719 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1725 if (XWINT (x
, i
) != XWINT (y
, i
))
1730 if (XINT (x
, i
) != XINT (y
, i
))
1732 if (((code
== ASM_OPERANDS
&& i
== 6)
1733 || (code
== ASM_INPUT
&& i
== 1))
1734 && locator_eq (XINT (x
, i
), XINT (y
, i
)))
1741 if (XTREE (x
, i
) != XTREE (y
, i
))
1746 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
1751 if (! rtx_renumbered_equal_p (XEXP (x
, i
), XEXP (y
, i
)))
1756 if (XEXP (x
, i
) != XEXP (y
, i
))
1763 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
1765 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
1766 if (!rtx_renumbered_equal_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
)))
1777 /* If X is a hard register or equivalent to one or a subregister of one,
1778 return the hard register number. If X is a pseudo register that was not
1779 assigned a hard register, return the pseudo register number. Otherwise,
1780 return -1. Any rtx is valid for X. */
1783 true_regnum (const_rtx x
)
1787 if (REGNO (x
) >= FIRST_PSEUDO_REGISTER
&& reg_renumber
[REGNO (x
)] >= 0)
1788 return reg_renumber
[REGNO (x
)];
1791 if (GET_CODE (x
) == SUBREG
)
1793 int base
= true_regnum (SUBREG_REG (x
));
1795 && base
< FIRST_PSEUDO_REGISTER
)
1797 struct subreg_info info
;
1799 subreg_get_info (REGNO (SUBREG_REG (x
)),
1800 GET_MODE (SUBREG_REG (x
)),
1801 SUBREG_BYTE (x
), GET_MODE (x
), &info
);
1803 if (info
.representable_p
)
1804 return base
+ info
.offset
;
1810 /* Return regno of the register REG and handle subregs too. */
1812 reg_or_subregno (const_rtx reg
)
1814 if (GET_CODE (reg
) == SUBREG
)
1815 reg
= SUBREG_REG (reg
);
1816 gcc_assert (REG_P (reg
));